REGULATORY CAPITAL - Subsidiaries with Regulatory Capital Requirements (Details) $ in Millions	Jun. 30, 2026 USD ($)
Cboe Trading
Regulatory Capital Requirement [Line Items]
Actual	$ 16.8
Minimum Requirement	1.2
BIDS Trading
Regulatory Capital Requirement [Line Items]
Actual	13.5
Minimum Requirement	0.2
Cboe Fixed Income
Regulatory Capital Requirement [Line Items]
Actual	6.8
Minimum Requirement	0.1
Cboe Europe
Regulatory Capital Requirement [Line Items]
Actual	58.8
Minimum Requirement	37.1
Cboe Chi-X Europe
Regulatory Capital Requirement [Line Items]
Actual	0.7
Minimum Requirement	0.1
Cboe NL
Regulatory Capital Requirement [Line Items]
Actual	14.6
Minimum Requirement	5.7
Cboe Clear Europe
Regulatory Capital Requirement [Line Items]
Actual	141.4
Minimum Requirement	88.8
CFE
Regulatory Capital Requirement [Line Items]
Actual	151.9
Minimum Requirement	40.8
Cboe SEF
Regulatory Capital Requirement [Line Items]
Actual	18.9
Minimum Requirement	2.5
Cboe Digital Exchange
Regulatory Capital Requirement [Line Items]
Actual	12.9
Minimum Requirement	0.0
Cboe Clear U.S.
Regulatory Capital Requirement [Line Items]
Actual	25.7
Minimum Requirement	14.3
Cboe Australia
Regulatory Capital Requirement [Line Items]
Actual	16.0
Minimum Requirement	$ 6.1